<?php
namespace extend\captcha;
class Captcha{
    private $charset = 'abcdefghkmnprstuvwxyzABCDEFGHKMNPRSTUVWXYZ23456789';//随机因子 
    private $code;//验证码
    private $codelen;//验证码长度
    private $width;//宽度
    private $height;//高度
    private $img;//图形资源句柄
    private $font;//指定的字体
    private $fontsize = 16;//指定字体大小
    private $fontcolor;//指定字体颜色
    //构造方法初始化
    public function __construct($codelen = 5, $width = 120, $height = 30){
        $this->codelen = $codelen;
        $this->width = $width;
        $this->height = $height;
        $this->font = ROOT_PATH . '/extend/Captcha/auxin.otf';//注意字体路径要写对，否则显示不了图片
    }
    //生成随机码
    private function createCode(){
        $_len = strlen($this->charset)-1;
        for ($i=0; $i<$this->codelen; $i++) {
            $this->code .= $this->charset[mt_rand(0, $_len)];
        }
    }
    //生成背景
    private function createBg(){
        $this->img = imagecreatetruecolor($this->width, $this->height);
        $color = imagecolorallocate($this->img, mt_rand(157, 255), mt_rand(157, 255), mt_rand(157, 255));
        imagefilledrectangle($this->img, 0, $this->height, $this->width, 0, $color);
    }
    //生成文字
    private function createFont(){
        $_x = $this->width / $this->codelen;
        for ($i=0; $i<$this->codelen; $i++) {
            $this->fontcolor = imagecolorallocate($this->img, mt_rand(0, 156), mt_rand(0, 156), mt_rand(0, 156));
            imagettftext($this->img, $this->fontsize, mt_rand(-30, 30), $_x*$i+mt_rand(1, 5), intval($this->height / 1.4), $this->fontcolor, $this->font, $this->code[$i]);
        }
    }
    //生成线条、雪花
    private function createLine(){
     //线条
        for ($i=0; $i<6; $i++) {
            $color = imagecolorallocate($this->img, mt_rand(0, 156), mt_rand(0, 156), mt_rand(0, 156));
            imageline($this->img, mt_rand(0, $this->width), mt_rand(0, $this->height), mt_rand(0, $this->width), mt_rand(0, $this->height), $color);
        }
     //雪花
        for ($i=0; $i<100; $i++) {
            $color = imagecolorallocate($this->img, mt_rand(200, 255), mt_rand(200, 255), mt_rand(200, 255));
            imagestring($this->img, mt_rand(1, 5), mt_rand(0, $this->width), mt_rand(0, $this->height), '*', $color);
        }
    }
    //输出
    private function outPut(){
        header('Content-type:image/png');
        imagepng($this->img);
        imagedestroy($this->img);
    }
    //对外生成
    public function img(){
        $this->createBg();
        $this->createCode();
        $this->createLine();
        $this->createFont();
        $this->outPut();
    }
    //获取验证码
    public function code(){
        return strtolower($this->code);
    }
}
